(a) Field of the Invention
The present invention relates to a stripper composition for a photoresist, and more particularly to a stripper composition for a photoresist which is capable of simplifying a gate wiring process of a TFT-LCD circuit, a semiconductor IC, etc.
(b) Description of the Related Art
LCD circuits and semiconductor ICs have very fine structures. These fine-structured circuits are prepared by: coating or applying a photoresist uniformly on an insulation layer such as a metal oxide layer or on a conductive metal layer such as an aluminum alloy layer, formed on a substrate; exposing and developing the photoresist to form a pattern; and etching the metal layer or insulation layer using a mask. Then, the photoresist pattern is removed to obtain the circuit.
In general, a double conductive layer comprising an upper layer (the first conductive layer) of aluminum or an aluminum alloy such as Al-Nd, and a bottom layer (the second conductive layer) of chromium, molybdenum, or an alloy thereof, is used for the conductive metal layer for gate wiring in components such as an LCD, rather than a single metal layer.
Recently, silver (Ag), having better reflectivity than Al-Nd, has often been used as a reflective electrode. That is, with the growing importance of medium- or small-sized TFT-LCDs in regard to portability of mobile phones and PDAs (personal digital assistants), silver has come to be used in the reflective LCD to improve the panel characteristics. However, Ag is more difficult to process than Al, and it is easily corroded due to poor chemical resistance. In addition, the elution of silver causes contamination of the chemical bath and affects processes following, which brings about a reduction of the layer thickness and loss of CDs.
An example of the patterning processes of such gate wiring comprises deposition of a double metal layer on a semiconductor substrate, application of a photoresist, exposure, developing, etching of the first conductive layer, hard baking and ashing, stripping of the photoresist (PR strip), and etching of the second conductive layer. However, this process takes a substantial amount of time because the PR strip is performed after hard baking and ashing.
The stripper used to remove the photoresist pattern should have good stripping ability at both low and high temperatures. Also, it should not leave Impurity particles on the substrate or corrode metal layers such as Al or Ag. In addition, it is preferred to be environment-friendly and harmless to humans.
In order to satisfy these requirements, several photoresist stripper compositions have been developed and are used. For general production lines, a photoresist stripper composition comprising monoisopropanolamine (MIPA), N-methylpyrrolidone (NMP), and carbitol is used. Although this composition does not leave reactive Impurities, it is impossible to simplify the gate process. Also, for the Ag layer, excessive corrosion makes it impossible to use this composition.
For general mass-production lines, a stripper composition comprising monoethanolamine (MEA), N-methylpyrrolidone (NMP), butyldiflycol (BDG), and dimethylsulfoxide (DMSO) is used. However, this composition leaves reactive impurities and it is impossible to simplify the gate process. Furthermore, it is impossible to remove the DMSO included in the stripper.
For another method, there is a stripper composition comprising monoisopropanolamine (MIPA), N-methylpyrrolidone (NMP), carbitol, sulfones, and glycols. Although this composition does not leave reactive impurities, it is impossible to simplify the gate process. It is also expensive and cannot be prepared in a 20L container for production lines.
In addition, there is a stripper composition comprising several compounds including an organic amine, an organic solvent like DMF, and a surfactant. However, although this composition has good stripping ability, it cannot realize simplification of the process.
The present invention was made in consideration of the problems of the prior art, and it is an object of the present invention to provide a high-performance stripper composition for a photoresist capable of simplifying the gate process of double conductive layers for TFT-LCDs or semiconductor ICs by reducing the stripping time more than 50%, which can contribute to productivity improvement and cost reduction.
It is another object of the present invention to provide a semiconductor device preparing process which is capable of significantly improving productivity through simplification of the gate process, and which does not corrode metal layers like Ag.
It is another object of the present invention to provide a semiconductor device prepared by said method.
In order to achieve the objects, the present invention provides a stripper composition for a photoresist comprising 20 to 60 wt % of monoethanolamine, 15 to 50 wt % of N,N-dimethylacetamide, 15 to 50 wt % of carbitol, and 0.1 to 10 wt % of gallic acid.
Furthermore, the present invention provides a semiconductor device preparing process comprising a step of photoresist stripping using a stripper composition comprising 20 to 60 wt % of monoethanolamine, 15 to 50 wt % of N,N-dimethylacetamide, 15 to 50 wt % of carbitol, and 0.1 to 10 wt % of gallic acid.
Furthermore, the present invention provides a stripper composition for photoresist comprising 20 to 60 wt % of monoethanolamine, 15 to 50 wt/o of N,N-dimethylacetamide, and 15 to 50 wt % of carbitol.
Furthermore, the present invention provides a semiconductor device preparing process comprising a step of photoresist stripping using a stripper composition comprising 20 to 60 wt % of monoethanolamine, 15 to 50 wt % of N,N-dimethylacetamide, and 15 to 50 wt % of carbitol.
Furthermore, the present invention provides a semiconductor device prepared by said methods.